Strong Storms and Downbursts July 28, 2011

On July 28th, 2011, multiple thunderstorms developed near a slowly moving cold front which spread across northeast Kansas. The very warm surface conditions led to an environment that was supportive of downbursts. A few of the thunderstorms quickly intensified, but with lack of any mid-level shear to support the updrafts; the storms quickly collapsed upon themselves, bringing strong downpours and damaging winds. The most intense of these downburst thunderstorms formed in Ottawa County and brought 70 to 80 mph winds to areas near Wells and Oak Hill. Numerous outbuildings were destroyed and trees uprooted as a result of the damaging wind gusts. Areas of Riley and Pottawatomie Counties also recieved strong winds, and in Jefferson County, a boating dock broke loose from the Lake Perry Marina.

The downburst signatures can be seen above in the green and red velocity field (left). The green color indicates movement toward a the radar and red indicates movement away from the radar. Four distinct downburst signatures appear in the velocity loop. Can you find them?

The following storm damage images were taken from Ottawa County Emergency Management at Ottawa State Lake .
On the top image, a shed was destroyed while on the bottom, large tree limbs were downed.